Liquid coatings are employed in building materials. Many roofs are covered with liquid coatings to form polymeric membranes. Liquid coatingsare especially useful for use over flat or low-slope surfaces, such as flat or low-slope roofing, and they can be field applied. Traditional field-applied coatings for roofs are based upon acrylic, urethane or silicone resins. Polymer modified asphalt or bitumen liquid coatings may also be used. These coatings are often spray applied over existing or new roofs where the substrate may include a variety of materials such as wood, concrete, insulation foam, or EPDM, asphalt, polyolefin membrane.
For example, as disclosed in U.S. Pat. No. 7,401,843, roofing coatings, such as polyurethane coatings, can be applied to a roof to form a single layer coating forming a waterproofing membrane with a thickness of at least 10 mils. Similarly, U.S. Pat. No. 7,803,867 discloses an acrylic-modified fluoropolymer for use over flat or low-slope roofing to provide a coating having very low VOC levels with improved weatherability, dirt pickup resistance, and stain blocking properties as compared to conventional acrylic, urethane and silicone coatings. Additionally, in U.S. Pat. No. 6,538,060, discloses elastomeric polyurethane interpenetrating network compositions that are developed by in situ reaction of polyols with different isocyanates and polyisocyanates in a bituminous material, such as asphalt, coal tar, polymer modified asphalt, oxidized, and unoxidized asphalt. The bituminous polyurethane interpenetrating network elastomers are suitable for a wide variety of applications including but not limited to roofing, new construction, and wall and foundation waterproofing applications.
There is a desire to improve the flame and fire resistance of building materials such as liquid coatings.